APPLICATION TO STRUCTURAL ANALYSIS OF ESPI,

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APPLICATION TO STRUCTURAL ANALYSIS OF
ESPI, HOLOGRAPHY AND 3D SHAPE MEASUREMENT
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Introduction
Strain gauge method
The measurement method is easy, and precision is
high Now the strain measurement method spreading
most widely
Measurement at a contact-type and fixed point
Measurement only for gauge pasting point Use
limit by environment, amount of strain, and
fatigue
Problems
It is necessity of non contact and full field
measurement
Three dimensional shape measurement
Holography interferometry measurement
Electronic Speckle Pattern Interferometry(ESPI)
measurement
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Three dimensional shape measuring system
3D coordinates of the object can be measured
Feature
Portable and generality are abundant
Measurement time is short
Three dimensional shape measuring system
The shape of Concrete Joint and Nagasaki Peaceful
Prayer was measured
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Shape measurement of Concrete Joint
Concrete Joint
3D shape data
Detailed 3D coordinates of Concrete Joint surface
was obtained
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3D shape measurement of Nagasaki Peaceful Prayer
Shape data is obtained by connecting point group
data, and pasting surface
From 8 directions
Point group data
Shape data
Detailed 3D coordinates of Nagasaki Peaceful
Prayer surface was obtained
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Holographic interferometry measuring system
Measurement of small deformation and vibration
are possible by obtaining interference fringes
Feature
Measurement time is short Measurement in
darkroom
Holographic interferometry measuring system
The vibration of Twisted Conical Shells and
Notched Specimen was measured
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Free vibration modes of Twisted Conical Shells
Mode of vibration
Specimen
8th mode 3289(Hz)
3522(Hz)
Frequencies and modes of vibration almost agree
with the FE analytical results
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Vibration modes of the Notched Specimen
Mode of vibration
Holography
FE analysis
3rd mode 520(Hz)
538(Hz)
Frequencies and modes of vibration almost agree
with the FE analytical results
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Electric Speckle Pattern Interferometry (ESPI)
measuring system
From an interference fringe of speckle provided
by interference of a laser, measurement of
displacement of an object is possible
Feature
Measurement under visible light is possible
Non contact and full field measurement
ESPI measuring system
The displacement of Tensioned membrane and
Defective Plate was measured
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Wrinkle measurement of Tensioned membrane
Specific in time and the place of the wrinkle
generation is necessary
Research of membrane structure
Wrinkle
Distribution of a minor principal strain
ESPI measuring system enables specific in the
wrinkle generation part
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Tensile Test of the Defective Plate
Specimen
Load - Maximum principal strain curve
The concentration of the strain was able to be
confirmed to the vicinity of the breaking side
at the small load level by ESPI measuring system
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Summary
Application of optical measurement technology to
structure
APPLICATION TO STRUCTURAL ANALYSIS
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Electric Speckle Pattern Interferometry(ESPI)
measuring system
Principle of ESPI
Speckle pattern
Optical system
laser beams
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Interference fringes
CCD
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lens
object
Increment of phase difference ?f to displacement
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